WASHINGTON (CNN) --He's not on any ballot this fall, but no politician has more at stake in the midterm elections than President Bush, whose ability to govern over the next two years and seek re-election in 2004 will be dramatically affected by next month's vote.

The outcome in the Senate will largely decide whether Bush can push through judiciary nominations, including potential Supreme Court nominations, and pursue his tax-cut plan while he continues to fight wars on terrorism and against Iraq.

Meanwhile, the White House is monitoring gubernatorial races to determine what sort of battleground he'll face in 2004 and whether he can rely on powerful friends in key states. Republicans could lose three governors in the midwest and another three in the northeast, for example, a loss that would leave Bush with less access to money, local campaign machinery and state policy ideas that he enjoyed in 2000.

Additionally, both parties are paying particularly close attention to gubernatorial races in Texas and Florida because of the president's personal attachment to both states (his brother Jeb is governor of Florida) and the national implications of GOP losses in those populous states.

And assuming Democrats hold the Senate, Bush will need to rely heavily on a GOP-controlled House to advocate the administration's agenda on Capitol Hill.

None of this is lost on Bush, of course, who has spent much of the last two years raising millions of dollars for GOP candidates across the country.

Nonetheless, some Republicans are preparing for the possibility they'll fall short, arguing that Bush's prospects for 2004 are actually buoyed by a midterm rout for the GOP. With Democrats running Congress, the president could demonize legislative leaders and use Capitol Hill as a "foil" with which to seek a second term in two years.

"The lesson I learned from 1996 is that the president speaks with one voice while Congress has 535. Let's decide who wins that argument," said Scott Reed, who managed former Sen. Bob Dole's presidential campaign in 1996. "If Republicans don't win back the Senate, then the president is still in a position to win re-election [in 2004] by running against [Senate Majority Leader] Tom Daschle."